Cahoon presents survey of Planktonic Protists

Organisms found in freshwater in parts of the region are important to study and survey because they form the basis of the food web, a UVa-Wise biologist said when presenting the research he and others conducted in Natural Tunnel State Park.

When he moved to southwestern Virginia, UVa-Wise biologist Bruce Cahoon was pleased to learn that the area had the reputation as one of the most biodiverse temperate regions in North America.

“I was surprised to find that very little work, none that I have found, has been published to document the micro biome, all microscopic organisms, living in the Cumberland Mountains,” Cahoon said.

He began collaboration with two students—Ashley Huffman and Anna Crowell—and with Megan Krager, a park ranger who now works at Bays Mountain Park in Kingsport, Tennessee, on a project on that topic.

“The project was an attempt to find and quantify all the microscopic protists (eukaryotic cells) living in the freshwater systems within Natural Tunnel State Park,” he explained. “Our approach was to collect water several times throughout the summer of 2016, filter all the microorganisms from the water, extract the DNA from those microorganisms, and then sequenced a single gene, to act as a ‘barcode’ to identify them,” Cahoon said.

Natural Tunnel State Park was selected because a Bioblitz was being conducted in that area in the spring of 2016, which made the park a good test area for this type of research.

“These organisms, although you can’t see them, are incredibly important since they form the basis of the food web,” he said. “All other life we can see with the naked eye could not exist without them, so we were interested in learning about the diversity of the invisible organisms that are all around us and affect us and our ecosystem.”

Cahoon, the Buchanan Endowed Chair of Biology at UVa-Wise, and the others found more than 300 different genera (taxonomic designation one step higher than species) living within Stock Creek, two streams feeding into it, and in an abandoned quarry that is inside the park.

“We also found that the microbes would be present in large numbers one week but gone the next,” he said explaining that the microbes would be replaced by a different microbe. According to Cahoon, that showed that the waterways are dynamic and change in ways individuals cannot see in short periods of time.

“We assume these changes are due to micro-climate changes or presence of basic nutrients available in the waterways,” he said.

Cahoon presented his work at UVa-Wise on Oct. 25, and he will present at the Southeastern Phycology Colloquium in Wilmington, North Carolina this weekend. The data in the presentation will serve as the basis of a manuscript that is under review for publication.

“To the best of our knowledge, there are no published studies of this type from anywhere in the United States, but similar ones have been published from France and Canada in the past couple of years,” he said. “I hope to have it published within the next year.”